This invention relates to a two-piece electrical connector for connecting a flexible flat cable (FFC) or a flexible printed circuit (FPC) to a connection object such as a printed circuit board (PCB) and, in particular, to such a two-piece connector having metallic shells for electromagnetic shielding which is adaptive for high-speed transmission.
A two-piece electrical connector of the type described is used in, for example, notebook type computers. Such a two-piece electrical connector comprises a cable connector member mounted on a FPC or FFC (which will collectively be referred to as "FPC") and a mating connector member mounted on a PCB. The cable connector member is mated with the mating connector member to establish the connection between the FPC and the PCB.
In the prior art, the FPC generally comprises an insulator sheet or film having two laminated layers in which a plurality of signal conductors are embedded for transferring electric signals. A ground pattern is generally coated on at least one outer surface of the insulator film as an electro-magnetic shielding in order to suppress the electro-magnetic interference generating noise.
JP-A-9 232039 discloses such a two-piece electrical connector which has metallic shells mounted on the outer surface thereof for protecting the connector from noise. A cable connector member in the known connector is provided with a cable fixture for fixing an end of the FPC to the cable connector member itself for establishing electrical and mechanical connection of the FPC and the cable connector member. The cable fixture is rotatably mounted on a connector housing of the cable connector member. That is, when the cable fixture is positioned at a first position or an open position, the one end of the FPC is loosely insertable in the cable connector member. When the cable fixture is angularly rotated to a second position or a fixing position, the one end of the FPC is pressed onto contact terminal portions in the cable connector member by the cable fixture so that the FPC is mechanically and electrically connected to the cable connector member. The cable connector has a metallic shell covering an outer surface of the connector housing and another metallic shell covering the cable fixture.
In the known connector, two pieces of different metallic shells are required for the cable connector member and another different metallic shell is required to a mating connector. Thus, metallic shells of three different shapes must be prepared and assembled to the two different connector members. This results in a high cost, complicate assembling operation, and difficulty of management and quality control of parts.
Further, in the known connector, the cable fixture is rotatably mounted on the connector housing. Therefore, the connector requires an increased mounting space in order to allow the rotation of the cable fixture. This results in difficulty of high density disposition of electric parts including the known connector.
In order to resolve the problems, a copending U.S. patent application Ser. No. 09/050,775 filed Mar. 30, 1998, now U.S. Pat. No. 6,066,000, proposes a two-piece electrical connector where fixing a FPC to a cable connector member is performed by a slider inserted together with one end portion of the FPC into a connector housing. A metallic shell fixedly supports the slider therein and is slidably fitted on the connector housing for providing the electromagnetic shielding. Insertion and removal of the slider for the connector housing are performed by a sliding operation of the metallic shell on the connector housing.
The connector proposed in the copending application described above will be referred to as a "prior connector", hereinafter.
However, both of the known connector and the prior connector still have various problems as described below.
The mating connector member mating with the cable connector member has a plurality of contacts of a pin type. There is a problem that the pin type contact is easy to bend when the cable connector member is connected thereto or removed therefrom.
Further, the cable connector member has contacts which have complicated structure. In particular, contacts of the prior connector has a complicated box-shaped structure for receiving the pin type contact. Therefore, it is difficult to establish the impedance matching. The impedance mismatching causes a problem for the high speed transmission.
Further, some of the contacts in cable connector member are arranged to come into contact with the ground pattern on the main surface of the FPC but has no electrical relation with the ground plate pattern on the back surface of the FPC. As a result, there is a disadvantage that grounding is incomplete.
Further, since ground ones of contacts of the mating connector member are not connected to the shell, ground condition is not maintained excellent if a ground signal flows through the ground contacts in the socket connector.
Still further, the cable connector member uses a rotating insulator or a slide insulator, and therefore, the number of the parts increases correspondingly. Further, since the height of the cable connector needs correspondingly an additional height for permitting rotation of the rotating insulator or the fitting of the slide insulator, there is such a disadvantage that the entire height is not reduced.